Investigations of Surface Micro Patterning Processes Development of Viable Ink Based Deposition Route for Inorganic Semiconducting Compounds Used in Thin Film Photovoltaics

Abstract

In this thesis work the possibilities of creating periodic surface micro-patterns in newlinetechnologically important photovoltaic thin film layers has been evaluated. The newlinecontribution of surface micro patterning towards minimizing the optical losses was studied newlinein detail. Attempts have been made to increase the surface area of the emerging thin film newlinesolar absorbers such as CZTSe, Sb2Se3 without increasing the total area using optical newlinelithography. The prospects of using suitable photoresist for the ordered growth of surface newlinetextured thin film layers and the improvement in optical absorption due to light trapping newlineeffects were also discussed in detail. The optical absorbance of the surface micro-patterned newlineCZTSe and Sb2Se3 thin film photovoltaic layers was improved to ~ 40 % and ~70% in newlinecomparison with the planar CZTSe and Sb2Se3 thin films. newlineSimilarly the transmittance of the top electrode layers such as Indium Tin Oxide newline(ITO) and Zinc Oxide (ZnO) and the reflectance of the bottom metal electrode layer such newlineas Molybdenum (Mo) were also improved by surface micro-patterning of the respective newlinelayers. The regular arrangement of low aspect ratio microstructures created on the surface newlineof thin film layers reduces the reflectance from the top transparent electrodes up to ~12%. newlineThe reflectance from the bottom Mo layer was improved to ~10%. Integration of such newlineperiodic micro-structures in all the layers opens up a promising perspective towards newlinerealizing the efficiency of thin film photovoltaic devices in near future newline